ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
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VII Congreso Ibérico de Agroingeniería y Ciencias Hortícolas: Innovar y Producir para el Futuro
No full textLa reducción de los costos económicos y ambientales en la producción ornamental es una exigencia creciente,
tanto desde la perspectiva del productor como del consumidor, llegando a ser un parámetro más de calidad. Esto
exige aumentar la eficiencia de las estructuras de la explotación y del uso de los insumos, entre los que se
encuentran los fertilizantes y también el agua asociada a ellos en las técnicas del cultivo sin suelo.
Ajustar los aportes de fertilizantes requiere el conocimiento de las necesidades nutritivas de las distintas especies
cultivadas en cada fase de crecimiento y bajo las condiciones de cultivo habituales de la zona productora.
Gran parte de la producción ornamental en la Comunidad Valenciana corresponde a plantas arbustivas, siendo
Nerium oleander dominante, cuyo cultivo en contenedor definitivo se inicia en Julio y finaliza cuando se
comercializa, en el mismo contenedor en el que han sido cultivadas, en estado de floración con botón cerrado,
desde finales de invierno y durante la primavera. Agronómicamente, pueden distinguirse 3 periodos de cultivo a
partir de la plantación de esquejes enraizados; 1) crecimiento vegetativo (desde plantación en contenedor
definitivo hasta octubre que alcanza el tamaño final), 2) mantenimiento y acumulación de reservas (noviembre a
febrero) y, 3) crecimiento reproductivo (floración) de marzo a abril.
Es necesario incorporar información muy precisa de la demanda de nutrientes por las raíces de la planta en
intervalos de tiempo cortos, particularizados para cada época y tipo de crecimiento, para el buen uso del sistema
de cultivo en sustrato y en contenedor. Para ello se diseñó y construyó un dispositivo aeropónico que lo permite.
Los resultados obtenidos indican que, al inicio de la primavera la planta da prioridad a su desarrollo radicular
frente al aéreo, como adaptación a unas condiciones de mayor demanda de transpiración. Tanto el aumento
observado de la tasa de absorción de agua, como de la relación Pf/Ps, indican una buena adaptación de la planta
a dichas condiciones. El trabajo concluye, destacando la conveniencia de reducir los aportes de fertilizantes
durante el invierno y la primavera, hasta la venta de las plantas, con el fin de aumentar la eficiencia de uso de los
abonos y minimizar el impacto sobre el medio ambiente, sin reducir ni el rendimiento ni la calidad
Predictive modelling of soil aluminium saturation as a basis for liming recommendations in vineyard acid soils under Mediterranean conditions
No full textSoil acidification is a process of degradation that becomes more pronounced as a result of various human activities, but can be controlled through appropriate soil management. Calcium, magnesium and phosphorus deficiencies along with aluminium (Al) toxicity are considered the major constraints to plant growth in acid vineyard soils. The main aim of this work was to develop a model for liming amendment recommendation in acid vineyard soils using two liming materials, dolomite and sugar foam. These were used at three doses: 900, 1800 and 2700kgha(-1) of calcium carbonate equivalent (CCE). Seven soil properties, namely pH in water, pH in 1M potassium chloride (KCl), phosphorus content, base saturation, calcium, magnesium, potassium and aluminium exchangeable contents, were monitored at two soil depths (0-30 and 30-60cm) during 3 years. The association among the soil properties, and with the soil acidity, was investigated through principal component analysis. This resulted in the selection of the aluminium saturation in effective cation exchange capacity (Al%ECEC) as the soil property to be modelled. According to the results of a subsequent analysis of variance (ANOVA), the Al%ECEC strongly depends on the dose (in CCE content) of the liming material independently of its dolomite or sugar foam nature. Besides, the dose effect is different depending on the soil depth and the sampling time. As a result, two quadratic models, one per soil depth and for the time of leaf drop stage, have been proposed to make liming recommendations in acid vineyard soils. These quadratic empirical models are comparable with the known linear Cochrane model using an f value between 1.5 and 2 in the range of doses studied, i.e. able to drop the exchangeable aluminium down to 50%. However, the models proposed in this work further provide (i) different dose recommendations for the arable and deeper soil layers, and (ii) confidence intervals for minimum and maximum additions of liming materials and, specifically, for these important soils dedicated to the growing of vines under Mediterranean conditions
Experimental Virus Evolution Reveals a Role of Plant Microtubule Dynamics and TORTIFOLIA1/SPIRAL2 in RNA Trafficking
Get PDFThe cytoskeleton is a dynamic network composed of filamentous polymers and regulatory proteins that provide a flexible structural scaffold to the cell and plays a fundamental role in developmental processes. Mutations that alter the spatial orientation of the cortical microtubule (MT) array of plants are known to cause important changes in the pattern of cell wall synthesis and developmental phenotypes; however, the consequences of such alterations on other MT-network-associated functions in the cytoplasm are not known. In vivo observations suggested a role of cortical MTs in the formation and movement of Tobacco mosaic virus (TMV) RNA complexes along the endoplasmic reticulum (ER). Thus, to probe the significance of dynamic MT behavior in the coordination of MT-network-associated functions related to TMV infection and, thus, in the formation and transport of RNA complexes in the cytoplasm, we performed an evolution experiment with TMV in Arabidopsis thaliana tor1/spr2 and tor2 mutants with specific defects in MT dynamics and asked whether TMV is sensitive to these changes. We show that the altered cytoskeleton induced genetic changes in TMV that were correlated with efficient spread of infection in the mutant hosts. These observations demonstrate a role of dynamic MT rearrangements and of the MT-associated protein TORTIFOLIA1/SPIRAL2 in cellular functions related to virus spread and indicate that MT dynamics and MT-associated proteins represent constraints for virus evolution and adaptation. The results highlight the importance of the dynamic plasticity of the MT network in directing cytoplasmic functions in macromolecular assembly and trafficking and illustrate the value of experimental virus evolution for addressing the cellular functions of dynamic, long-range order systems in multicellular organisms
Quantitative trait loci affecting reproductive phenology in peach
Get PDFBackground: The reproductive phenology of perennial plants in temperate climates is largely conditioned by the duration of bud dormancy, and fruit developmental processes. Bud dormancy release and bud break depends on the perception of cumulative chilling and heat during the bud development. The objective of this work was to identify new quantitative trait loci (QTLs) associated to temperature requirements for bud dormancy release and flowering and to fruit harvest date, in a segregating population of peach. Results: We have identified QTLs for nine traits related to bud dormancy, flowering and fruit harvest in an intraspecific hybrid population of peach in two locations differing in chilling time accumulation. QTLs were located in a genetic linkage map of peach based on single nucleotide polymorphism (SNP) markers for eight linkage groups (LGs) of the peach genome sequence. QTLs for chilling requirements for dormancy release and blooming clustered in seven different genomic regions that partially coincided with loci identified in previous works. The most significant QTL for chilling requirements mapped to LG1, close to the evergrowing locus. QTLs for heat requirement related traits were distributed in nine genomic regions, four of them co-localizing with QTLs for chilling requirement trait. Two major loci in LG4 and LG6 determined fruit harvest time. Conclusions: We identified QTLs associated to nine traits related to the reproductive phenology in peach. A search of candidate genes for these QTLs rendered different genes related to flowering regulation, chromatin modification and hormone signalling. A better understanding of the genetic factors affecting crop phenology might help scientists and breeders to predict changes in genotype performance in a context of global climate change
Addition of Cholesterol-Loaded Cyclodextrins to the Thawing Extender: Effects on Boar Sperm Quality
No full textThe aim of the present study was to evaluate the effect that the addition of cholesterol‐loaded cyclodextrins (CLC) to the thawing extender has on the quality of frozen‐thawed boar sperm. Pooled semen (n = 5) from three boars was used for the experiments. The semen was cryopreserved with an egg‐yolk‐based extender, it was diluted after thawing in Beltsville thawing solution (BTS) supplemented with different concentrations of CLC (0, 12.5, 25, 50 or 100 mg/500 × 106 sperm), and these samples were incubated at 37°C for 150 min. The following parameters of sperm quality were evaluated 30 and 150 min after incubation: sperm with intact plasma membrane (SIPM; %), sperm with normal acrosomal ridge (NAR; %), total motile sperm (TMS; %), progressively motile sperm (PMS; %) and kinetic parameters. Both SIPM and NAR increased (p < 0.05) when the thawing extender was supplemented with 12.5, 25 and 50 mg CLC/500 × 106 sperm. Nevertheless, motility decreased (p < 0.05) when the concentration of CLC exceeded 12.5 mg CLC/500 × 106 sperm. In conclusion, our results suggest that the supplementation of thawing extenders with CLC improves sperm viability and reduces acrosome damage after freezing/thawing
Manganese Deficiency is Associated with Histological Changes in Date Palm Fronds Showing Brittle Leaf Disease Symptoms
No full textSeveral diseases, pests and physiological disorders threat date palm life. Among them, Brittle leaf disease or, in French, Maladie des feuilles cassantes (MFC) is a lethal disease that has acquired alarming proportions since the 1960s, when it was first observed in southern Tunisia. Up to now no causal agent has been found. Previous studies have reported that brittle fronds are deficient in manganese but the mechanisms involved in symptom expression have not yet been identified. In this study, an anatomical investigation was carried out in order to identify the deleterious effect of MFC on the development and structure of palm fronds. Results showed that in old healthy fronds the major tissue is schlerenchyma, which is characterized by very thick lignified cell walls and is often associated with conducting tissue. Indeed, large vessels are surrounded by schlerenchyma fibers that are strongly lignified when compared with those of young fronds. Diseased young fronds have almost the same shape as the healthy young fronds. Nevertheless, in old diseased fronds MFC induces important structural changes. Xylem and phloem vessels are larger, taking more space through the fibers that are smaller in number and size, and tighter. The larger diameter of the lumen and the lower thickness of the fibers present in the fronds in advanced disease stages, decreases the lignin content of cells walls, leading to an increased frond friability, which gives "the brittle leaf disease" its name
Early detection of mechanical damage in mango using NIR hyperspectral images and machine learning
No full textMango fruit are sensitive and can easily develop brown spots after suffering mechanical stress during postharvest handling, transport and marketing. The manual inspection of this fruit used today cannot detect the damage in very early stages of maturity and to date no automatic tool capable of such detection has been developed, since current systems based on machine vision only detect very visible damage. The application of hyperspectral imaging to the postharvest quality inspection of fruit is relatively recent and research is still underway to find a method of estimating internal properties or detecting invisible damage. This work describes a new system to evaluate mechanically induced damage in the pericarp of ‘Manila’ mangos at different stages of ripeness based on the analysis of hyperspectral images. Images of damaged and intact areas of mangos were acquired in the range 650–1100 nm using a hyperspectral computer vision system and then analysed to select the most discriminating wavelengths for distinguishing and classifying the two zones. Eleven feature-selection methods were used and compared to determine the wavelengths, while another five classification methods were used to segment the resulting multispectral images and classify the skin of the mangos as sound or damaged. A 97.9% rate of correct classification of pixels was achieved on the third day after the damage had been caused using k-Nearest Neighbours and the whole spectra and the figure dropped to 91.4% when only the most discriminant bands were used
Acta Horticulturae
No full textAlternative and more practical methods than stem water potential (Ψs) and stomatal conductance (gs) are needed for detecting plant water stress when regulated deficit irrigation (RDI) strategies are to be applied. The aim of this experiment was to assess the usefulness of sap flow and canopy temperature (Tc) measurements, as plant water stress indicators in citrus trees compared with more classical methods like Ψs or gs. The experiment was performed during the summer of 2011 in a “Clementina de Nules” orchard undergoing RDI. Sap flow was determined by means of the compensated heat pulse method in well-watered and RDI trees. Tc was measured continuously with infrared thermometers (IRTs) mounted over the canopies pointing vertically downward but also weekly with an infrared hand-operated thermographic camera taking frontal images of the sunlit side of the crowns. Concurrently, Ψs and gs were also measured on all the trees. Results showed that the evolution of relative transpiration, obtained with the sap flow gauges, was in agreement with the water deficit applied. The values of Tc obtained with the IRTs normalized by air temperature (e.g., Tc - Ta) were in general poorly related with Ψs and gs. However, when Tc was obtained from thermal imaging there was a good correlation with Ψs in days of relatively high stress (i.e., when Ψs differences among treatments were > 1.0 MPa). Ψs, gs and Tc obtained from thermal images were significantly correlated with the average fruit weight at harvest. The best correlation was that of thermographic Tc followed by Ψs and gs. Overall, results showed that both sap flow and Tc measurements can detect plant water stress in cases of severely stressed citrus trees. The determination of Tc from thermal imaging, which integrates a large number of leaves in the measurement, was better than the IRTs method for detecting plant water stress
Next generation haplotyping to decipher nuclear genomic interspecific admixture in Citrus species: analysis of chromosome 2
Get PDFBackground: The most economically important Citrus species originated by natural interspecific hybridization between four ancestral taxa (Citrus reticulata, Citrus maxima, Citrus medica, and Citrus micrantha) and from limited subsequent interspecific recombination as a result of apomixis and vegetative propagation. Such reticulate evolution coupled with vegetative propagation results in mosaic genomes with large chromosome fragments from the basic taxa in frequent interspecific heterozygosity. Modern breeding of these species is hampered by their complex heterozygous genomic structures that determine species phenotype and are broken by sexual hybridisation. Nevertheless, a large amount of diversity is present in the citrus gene pool, and breeding to allow inclusion of desirable traits is of paramount importance. However, the efficient mobilization of citrus biodiversity in innovative breeding schemes requires previous understanding of Citrus origins and genomic structures. Haplotyping of multiple gene fragments along the whole genome is a powerful approach to reveal the admixture genomic structure of current species and to resolve the evolutionary history of the gene pools. In this study, the efficiency of parallel sequencing with 454 methodology to decipher the hybrid structure of modern citrus species was assessed by analysis of 16 gene fragments on chromosome 2. Results: 454 amplicon libraries were established using the Fluidigm array system for 48 genotypes and 16 gene fragments from chromosome 2. Haplotypes were established from the reads of each accession and phylogenetic analyses were performed using the haplotypic data for each gene fragment. The length of 454 reads and the level of differentiation between the ancestral taxa of modern citrus allowed efficient haplotype phylogenetic assignations for 12 of the 16 gene fragments. The analysis of the mixed genomic structure of modern species and cultivars (i) revealed C. maxima introgressions in modern mandarins, (ii) was consistent with previous hypotheses regarding the origin of secondary species, and (iii) provided a new picture of the evolution of chromosome 2. Conclusions: 454 sequencing was an efficient strategy to establish haplotypes with significant phylogenetic assignations in Citrus, providing a new picture of the mixed structure on chromosome 2 in 48 citrus genotypes
Genetic variability and evolution of broad bean wilt virus 1: role of recombination, selection and gene flow
No full textAnalysis of four genomic regions from 37 geographically diverse isolates of broad bean wilt virus 1 (BBWV-1) showed high genetic diversity in comparison to most plant viruses. Comparison of synonymous and nonsynonymous substitutions of the small coat protein gene (SCP) revealed negative selection for most amino acid positions. Phylogenetic analysis of SCP showed that some BBWV-1 isolates from distant geographical areas were genetically close, suggesting long-distance migration. Analysis of genetic differentiation revealed high gene flow between Spanish and Near Eastern subpopulations, which were separated from North-Central and South-Eastern European subpopulations. Finally, putative recombinant and reassortant genomes were also identified